From landrace to modern hybrid broccoli: the genomic and morphological domestication syndrome within a diverse B. oleracea collection

Abstract

Worldwide, broccoli (Brassica oleracea var. italica) is among the most economically important, nutritionally rich, and widely-grown vegetable crops. To explore the genomic basis of the dramatic changes in broccoli morphology in the last century, we evaluated 109 broccoli or broccoli/cauliflower intermediates for 24 horticultural traits. Genotype-by-sequencing markers were used to determine four subpopulations within italica: Calabrese broccoli landraces and hybrids, sprouting broccoli, and violet cauliflower, and to evaluate between and within group relatedness and diversity. While overall horticultural quality and harvest index of improved hybrid broccoli germplasm has increased by year of cultivar release, this improvement has been accompanied by a considerable reduction in allelic diversity when compared to the larger pool of germplasm. Two landraces are the most likely founding source of modern broccoli hybrids, and within these modern hybrids, we identified 13 reduction-in-diversity genomic regions, 53 selective sweeps, and 30 (>1 Mbp) runs of homozygosity. Landrace accessions collected in southern Italy contained 4.8-fold greater unique alleles per accessions compared to modern hybrids and provide a valuable resource in subsequent improvement efforts. This work broadens the understanding of broccoli germplasm, informs conservation efforts, and enables breeding for complex quality traits and regionally adapted cultivars.

Effects of Growing Cycle and Genotype on the Morphometric Properties and Glucosinolates Amount and Profile of Sprouts, Microgreens and Baby Leaves of Broccoli (Brassica oleracea L. var. italica Plenck) and Kale (B. oleracea L. var. acephala DC.)

“…Another element that can modify the GLS profile is genotype; in this framework, analyses of the GLS composition of underexploited landraces and new varieties of B. oleracea crops should be conducted through a more exhaustive evaluation of their agronomic performances and biological value for human health in a wider range of environmental conditions, such as the Mediterranean and Atlantic areas [25,26].…”

Building a foundation for gene family analysis in Rosaceae genomes with a novel workflow: A case study in Pyrus architecture genes

“…Crops, most of which have gone through more than ten thousand years of domestication to meet human requirements, have a wide diversity in forms, sometimes even within the same species ( Stansell and Björkman, 2020 ). One such example is in the Brassica species, where B. rapa encompasses morphologically diverse vegetables such as Chinese cabbage, turnips, and mizuna; and cabbage, stem kale, and Brussels sprouts are the same biological species, B. oleracea .…”

Genetic variability among broccoli genotypes based on biochemical and molecular traits

“…This species is the result of the selection and accumulation of mutations during the domestication process of B. sylvestris. Its center of origin is the Mediterranean region (Stansell & Björkman, 2020). Broccoli germplasm is divided into two main commercial groups: ramoso, related to biotic and abiotic stresses (Melo et al, 2017).…”